Abstract This article discusses the issues related to the possibility of realization of collision cyberattacks (based on hash collisions). Since post–quantum cryptography has become relevant, classical cryptosystems do not provide the sufficient resistance to the modern quantum cyberattacks. Systems based on outdated hashing algorithms become vulnerable to cyberattacks with hash collision. As replacement for unreliable algorithms, such as various modifications of MD5 and SHA–1, new algorithms have been created, for example, SHA–3 standard based on the Keccak function and AES–based hashing. This article discusses modern collision cyberattacks and possible methods of their detection. Because of this study, theoretical description of cyberattacks with hash collision was considered; modern cyberattacks on hash collisions and possible ways of detecting and countering them (weak hash detection) are described; software tool that detects vulnerable and unreliable hash is implemented; software testing is carried out. Based on the conducted research, it can be concluded that the main advantages of implementing software tool are effective detection of vulnerable hash, the ability to generate new hash protected from collisions, convenient and user– friendly interface, small memory requirements and small size of the program code.